Date seeds or pits are one of the agricultural by-products contributing to food waste that is given only to animals and the rest of them through without use. Many industrialized processes started to work with this lignocellulosic polymer in many products, even for human consumption animals, or other things like biofuels, etc. In this study, the extraction of holocellulose was treated with rumen liquor after de-fatted and de-lignin of whole date pits. After fermentation or incubation for 24 h, the results were increasing in GP (P 0.001), DOM (P 0.001), total VFA (P = 0.011), and propionate (P 0.001) concentrations, as well as estimated energy (ME and NE) (P 0.05) and microbial protein (P = 0.017) values. However, the inclusion of H-C in the diet displayed linear reductions in the net CH₄ production (ml/kg DOM; P = 0.002), protozoa abundance (P = 0.027), acetate (P = 0.029), and butyrate (P 0.001), and the estimated net H₂ production concentration (P = 0.049). After treated with rumen physiochemical characteristics were studied, like the chemical compositions showed significant changes (P 0.5) in cellulose, protein, and fat contents(25.0, 18.0, and 6.0 g/100 g sample, respectively), the solubility of the HCJR(15.0 g/L) and HCJS (58.0 g/L) fractions compared to the control (4.0 g/L), the absorption capacity (16.0, 16.0, and 15.0 g/100 g sample) were insignificant changed for HCJS, HCJR dual fraction, and H-C fraction, respectively, two glass transitions were observed for the control (G₁:138 and G₂:143 °C) and HCJS fraction (G₁:38 and G₂:89 °C), indicating less homogeneity in the composition of these fractions compared to the HCJR, which showed a single glass transition(G₁:154°C). Higher solid melting temperature in the case of HCJR extract(182 °C) indicated a lower degradability rate compared to the HCJS fraction(123 °C), the crystallinity structure of the H-C (92.0%) was altered due to rumen degradation in the case of HCJR (84.0%) and HCJS (95%) fractions that were confirmed by morphological surface changes of the HCJR (less ordered and higher porosity) and HCJS (stiffened surface with spherical lignin) fractions compared to the HC. Hence, holocellulose could be considered a potent feed additive for animals and, furthermore, may be used in food industries and other production areas.